Imagine you want to disable a car. You could open the hood and unplug the battery. Or you could fire a missile at it.
Antibiotics are like unplugging the battery. It only works if you can get under the hood and it wouldn't work at all on electric cars. It's selective.
Alcohol is like a missile. It destroys everything. You can't evolve resistance to missiles. You just have to hope you don't get hit.